What are Polaroids?

What is a polaroid?

What do you mean by the term crossed polaroids?

What are radio-isotopes? What are their applications?

What is a tissue? What are its kinds?

Two polaroids are placed at 90^@ to each other and the transmitted intensity is zero .What happens,when one more polaroid is placed betwen these two,bisectiing the angle between them.How will the intensity of transmitted light vary on further rotatint the third polaroid?

Write two uses of polaroids?

Two polaroids are placed at 90^@ to each other.What happens,when(N-1) more polaroids are inserted between them?Their axis are equally spaced.How does the trnsitted intensity behave ffor large N?